Polyvinyl alcohol fuller's earth clay nanocomposite films

Nano fuller's earth was prepared by milling and subsequent sonication of clay. The polyvinyl alcohol (PVA) and PVA ‐Nano clay composite films were prepared by solution casting method. The films were characterized for their structural, mechanical, and thermal properties using electron microscopes (SEM, TEM), Tensile Tester, dynamic mechanical analyzer (DMA), thermo gravimetric analyzer (TGA), and Raman spectroscopy. The nanocomposite films showed improvement in mechanical properties, viscoelastic behavior as well as resistance towards thermal degradation. Uniform distribution of clay due to intimate interaction between clay and polymer appears to be the cause for improved properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Formation,potential and abatement of plume from wet cooling towers: A review

In recent years the visible impact of the release from wet cooling tower to the atmosphere has become a matter of greater concern. In the past visible plumes were accepted as the inevitable consequence of industrial activities and a sign of thriving manufacturing industry. Plumes from combustion plant may be visible and colored for a variety of reasons. Some are associated with the combustion process itself, such as excessive quantities of nitrogen dioxide causing a brown tinge to plumes or the release of small particles, and/or aerosols, in the plume which scatter light. These factors can be tackled by modification of the combustion process and the introduction of emission control technology. However, the most common cause of plume visibility, and the reason that chimneys attract public attention, is the presence of condensed water vapor in plumes. In this paper attempt has been made to present an overview of the previous research work on the plume from wet cooling towers, which describes the previous work done of few researchers on the formation, potential and abatement of plumes besides, the numerical analysis of wet cooling towers for a typical set of operating parameters.     

Influence of lactic acid on degradation and biocompatibility of electrospun poly(ε‐caprolactone) fibers

Electrospinning of a poly(ε‐caprolactone) (PCL)/lactic acid (LA) blend was investigated to fabricate electrospun PCL fibers with improved biodegradability and biocompatibility for biomedical applications. Simple blending of PCL solution with various amounts of LA was used for electrospinning, and the physicochemical properties of the as‐fabricated mat were evaluated using various techniques. Scanning electron microscopy showed that fiber diameter decreased with increasing amount of LA. Fourier transform infrared spectroscopy and thermogravimetric analysis also revealed that LA was successfully incorporated in PCL fibers. The presence of LA can accelerate the biodegradation of PCL fibers and enhance the hydrophilicity of a membrane. The adhesion, viability and proliferation properties of osteoblast cells on the PCL/LA composite fibers were analyzed using in vitro cell compatibility tests which showed that LA can increase the cell compatibility of PCL fibers. Additionally, subsequent conversion of LA into calcium lactate by neutralization with calcium base can provide Ca²⁺ ions on the fiber surface to promote the nucleation of CaPO₄ particles. © 2013 Society of Chemical Industry     

Impact of Industry Structure and Product Characteristics on the Structure of B2B Vertical Hubs

Business-to-business (B2B) vertical hubs are expected to play an important role in the digital economy and add value by reducing inefficiencies in industrial procurement and enabling efficient interfirm interactions and collaborations. The last few years have witnessed both a proliferation of business models underlying these hubs and the failure of many of these hubs. This study identifies key structural dimensions of vertical hubs and develops a conceptual framework to characterize vertical hubs. We draw from the industrial organization theory and the marketing literature to examine the relationship between the characteristics of the vertical hubs, those of the industries they serve, and the products transacted through the hubs. Based on data collected from 63 B2B vertical hubs, we test our hypotheses relating industry and product characteristics to the structure of vertical hubs. The results provide modest support to our theoretical proposition that the characteristics of vertical hubs are likely to be shaped by the industry and product characteristics. We interpret the results and discuss the implications of the study for research and practice.     

Microstructure and Mechanical Properties of Cu-Ag-Zr Alloy

The Cu-3Ag-0.5Zr alloy was produced by vacuum induction melting and subsequently processed through hot forging and rolling. Detailed microstructural characterization of solution-treated (ST) specimen shows three types of phases: Cu matrix, zirconium-rich phase, and Cu-Ag-Zr intermetallic phase. Transmission electron microscopy studies together with energy-dispersive x-ray spectroscopy analysis established the presence of Zr-rich large particles in the ST condition. Aging at 450 °C for 4.5 h after solution treatment resulted in the formation of uniformly distributed fine spherical silver precipitates with an average diameter of 9.0 ± 2.0 nm. Consequently, room temperature yield strength (YS) and ultimate tensile strength (UTS) of the aged specimen increased by 110% and 15%, respectively, compared to those of 120 and 290 MPa of the ST specimen. At elevated temperature, the YS decreased to 146 and 100 MPa at 540 and 640 °C, respectively, for the aged sample. On the contrary, the YS increased to 140 MPa at 540 °C, and thereafter a decrease was observed with a value of 105 MPa at 640 °C for the ST sample. This decrease in YS at higher temperatures is attributed to coarsening of precipitates and dissolution of the precipitates, whereas an increase in YS is attributed to in-situ aging of the samples.     

Combined experimental and kinetic modeling studies for the conversion of gasoline range hydrocarbons from methanol over modified HZSM-5 catalyst

The reaction was carried out in fixed bed reactor. The effect of process variables on the activity of oxalic acid treated 0.5 wt% ZnO/7 wt% CuO/HZSM5 catalyst for the conversion of methanol to gasoline range hydrocarbons was studied. The catalyst was prepared by incipient wetness impregnation method. After impregnation the catalyst was treated with oxalic acid. The validity of kinetic model proposed for the methanol to gasoline range hydrocarbon process at zero time on stream was studied, from the experimental results obtained in a wide range of operating conditions. The kinetic parameters for various models were calculated by solving the equation of mass conservation in the reactor for the lumps of the kinetic models. The kinetic model fitted well for simulating the operation in the fixed bed reactor in the range of 635 to 673 K, with regression coefficient (R²) higher than 0.96.     

Use of novel permeable membrane and air cathodes in acetate microbial fuel cells

In the existing microbial fuel cells (MFCs), the use of platinized electrodes and Nafion^® as proton exchange membrane (PEM) leads to high costs leading to a burden for wastewater treatment. In the present study, two different novel electrode materials are reported which can replace conventional platinized electrodes and can be used as very efficient oxygen reducing cathodes. Further, a novel membrane which can be used as an ion permeable membrane (Zirfon^®) can replace Nafion^® as the membrane of choice in MFCs. The above mentioned gas porous electrodes were first tested in an electrochemical half cell configuration for their ability to reduce oxygen and later in a full MFC set up. It was observed that these non-platinized air electrodes perform very well in the presence of acetate under MFC conditions (pH 7, room temperature) for oxygen reduction. Current densities of −0.43 mA cm⁻² for a non-platinized graphite electrode and −0.6 mA cm⁻² for a non-platinized activated charcoal electrode at −200 mV vs. Ag/AgCl of applied potential were obtained. The proposed ion permeable membrane, Zirfon^® was tested for its oxygen mass transfer coefficient, K₀ which was compared with Nafion^®. The K₀ for Zirfon^® was calculated as 1.9 × 10⁻³ cm s⁻¹.     

Fabrication of multifunctional TiO2–fly ash/polyurethane nanocomposite membrane via electrospinning

In this study, we demonstrate the fabrication of multifunctional composite polyurethane (PU) membrane from a sol gel system containing TiO₂ and fly ash (FA) nanoparticles (NPs). The adsorptive property of FA and photocatalytic property of TiO₂ can introduce different functionalities on PU mat for water purification. Different types of PU nanofiber mats were prepared by varying the composition of NPs in blend solution. FE-SEM, TEM, TGA, XRD, UV–visible spectra, and water contact angle measurement confirmed the incorporation of FA and TiO₂ NPs on/into PU nanofibrous mat. The influence of NPs on PU membrane was evaluated from the adsorption of heavy metals (Hg, Pb), removal of dyes (methylene blue), antibacterial activity, and water flux. The improvement of all these activities is attributed to the adsorptive property of FA and photocatalytic/hydrophilic property of TiO₂ NPs. Therefore, as-synthesized composite membrane can be utilized as an economically friendly filter media for water purification.     

Synthesis and characterization of spider‐web‐like electrospun mats of meta‐aramid

The effect of salt formation during condensation polymerization on the morphology of electrospun meta‐aramid fibers was investigated. The presence of a by‐product salt (CaCl₂) improved the electrospinability of the meta‐aramid solution and induced the formation of a spider‐web‐like structure in the mat. The effect of the concentration of the solution and the applied voltage on the formation of the spider‐web‐like fibrous structure was investigated. Field emission scanning electron microscopy images indicated that thin fibers were uniformly distributed with thick fibers throughout the mats in the form of a spider‐web‐like structure. Thermogravimetric analysis showed that the thermal stability of the electrospun mat was affected by CaCl₂. The observed enhancement in the thermal and mechanical properties of the mats, which was attributed to the formation of the spider‐web‐like structure, may increase the number of potential applications of meta‐aramids, such as water/air filtration, protective clothing and electrical insulation. Copyright © 2012 Society of Chemical Industry     

Machine learning based position-rendering algorithms for radioactive particle tracking experimentation

Radioactive particle tracking (RPT) is one of the most widely used non-intrusive velocimetry technique for multiphase reactors. The large volume of interrogation and the presence of internals limit the application of RPT in large-scale real-world systems. The main challenge lies in having fast reconstruction algorithms applicable to conventional (i.e., bubble columns, fluidized beds, etc.) as well as new vessels. In this contribution, a reconstruction methodology is proposed based on machine learning. Three machine-learning algorithms, namely, artificial neural network (ANN), support vector regression (SVR), and relevance vector regression (RVR), have been employed for RPT reconstruction. The results show that the position reconstruction accuracy of SVR was best for all cases and that the accuracy of RVR was comparable to SVR for large training datasets. Whereas, in terms of reconstruction speed, RVR outperforms SVR significantly, owing to sparser RVR model. SVR and RVR based reconstruction algorithms expedite the position reconstruction.